1. Field of the Invention
The present invention relates to a reflection-type photointerrupter for detecting an object by utilizing light reflection.
2. Description of the Related Art
FIG. 7 illustrates a photointerrupter X4, which is an example of conventional reflection-type photointerrupter. The photointerrupter X4 includes a substrate 91, a light emitting element 92, a light receiving element 93, a molded resin 94 and a light-shielding resin 95. The substrate 91 is in the form of a rectangular flat plate and made up of a base member 91a and a wiring portion 91b. The light emitting element 92 is arranged on the substrate 91 to emit infrared light. The light receiving element 93 is arranged on the substrate 91 to receive light and generate an electromotive force corresponding to the amount of light received. The molded resin 94 is provided on the substrate 91 to cover the light emitting element 92 and the light receiving element 93. The light-shielding resin 95 is arranged between the light emitting element 92 and the light receiving element 93. In the photointerrupter X4, when the light emitted from the light emitting element 92 is reflected by an object to be detected and received by the light receiving element 93, the light receiving element 93 generates an electromotive force corresponding to the amount of light received. Based on the electromotive force, the object is detected. This type of conventional photointerrupter is disclosed in JP-A-2007-13050, for example.
In recent years, in accordance with the size reduction of electronic devices (such as foldable mobile phones) in which a photointerrupter is to be incorporated, the thickness reduction of a photointerrupter is strongly demanded. However, the above-described photointerrupter X4 cannot sufficiently meet the demand for the thickness reduction.
The present invention has been proposed under the circumstances described above. It is therefore an object of the present invention to provide a reflection-type photointerrupter which is suitable for thickness reduction.